The Painted Turtle (Chrysemys picta) is a reptile that is common in southern Canada, the United States, and northern Mexico and is a water turtle related to other water turtles such as sliders and cooters. This turtle lives in ponds, lakes, marshes, and in slow-moving rivers that have soft, muddy bottoms. The maximum carapace size, or shell length, for painted turtles is 10 inches, or 25 cm. Its shell is used to protect it from its predators. The underside, or plastron, of the Painted turtle's shell has a beautiful design that (hence the name) looks like it is painted. The plastron can be solid yellow, mostly yellow with a pattern in the center, or may be a complicated pattern of yellow and red. There are yellow or red lines on the painted turtle's head, and limbs. The skin tone of the painted turtle varies from olive green to solid black. The Painted Turtle is the only species in the genus Chrysemys. It comprises 4 sub-species: the Eastern, Southern, Midland, and Western painted turtles.

The Western Painted Turtle (C. p. bellii), is the official reptile of the U.S. state of Colorado.

Mating begins shortly after the turtles have emerged from hibernation when the water temperature is still low. Mating may also occur in the fall. The breeding season lasts from late spring to early summer. Males begin to breed when they reach maturity, usually at 70-95 mm plastron length when they are three to five years old. Females take longer to mature (6-10 years) and are larger at maturity. Painted turtles are amniotes which requires females to nest on land. Females prefer soft, sandy soil with good exposure to the sun for their nest site. Nests are dug with the turtle's hind feet, usually within 200 meters of water. The nest is no deeper than 10 to 12 centimeters. The females will lay 4 to 15 oval, soft shelled eggs, in a flask-shaped hole. The eggs are elliptical, white to off-white and are mostly smooth with slight pits. Female turtles may lay up to five clutches of eggs per season although typically, they will lay only one or two clutches. Once the eggs are laid the mother will cover the hole with dirt or sand and leave the nest unattended. Painted turtle eggs hatch 72 to 80 days after they are laid. Once the young hatch and dig out of the nest, they are immediately independent.

Painted turtles are most active from March to October. During the winter painted turtles hibernate by burying themselves deep in the mud beneath streams and ponds. The mud insulates the turtle, which helps prevent freezing during the harsh winter months. The turtle may submerge itself in up to .9 meters (3 ft) of mud under less than 1.8 meters (6 ft) of water. Painted turtles can survive without oxygen at 3° Celsius (37.4°F) for up to five months, longer than any other known air-breathing vertebrate. In order to survive during hibernation, the turtle must prevent lactic acid from building up in its body. The turtle accomplishes this by slowing its metabolic rate, which in turn lowers the rate of lactic acid production. It then uses magnesium and calcium stored in its shell to buffer and neutralize lactic acid. Northern populations of painted turtle may remain dormant for four to six months. More southerly populations may become active during warm periods. When emerging from a dormant period, most turtles will not begin to eat again until the water temperature has reached approximately 15.5° Celsius (60°F)..

The painted turtle spends the majority of its time in the water, but it can often be seen lying in the sun on floating logs or on rocks by the shore. This behavior is called basking. Some turtles bask simply by floating on the surface of the water. Painted turtles bask because they cannot generate heat or regulate their own body temperature. Instead, they rely on heat from the sun to maintain their body temperature for them. Basking episodes generally last for two hours at a time. Basking must be done cautiously, as overheating can kill a turtle within minutes.

Painted turtle hatchlings prefer a carnivorous diet of larvae, crickets, beetles and maggots. Mature turtles may include plants such as duckweed, water lilies and algal matter in their diet. Painted turtles may also eat worms, leeches, crayfish, tadpoles, frogs, slugs, snails, small clams, small fish, and a variety of insects. Local populations of painted turtles may be entirely carnivorous, entirely herbivorous or omnivorous. Captive painted turtles will eat fresh and canned fish, lettuce, cantaloupe, frozen smelt, earthworms, newborn mice, carrots, commercial trout food and store bought turtle pellets like the brand Reptomin. They should not be fed iceberg lettuce as it contains no nutrients. .

Painted turtles forage for food along the bottom of bodies of water and among clumps of algae and water plants. They may also skim the surface of a calm pond while holding their mouths open . This behavior is known as neustophagia . Painted turtles eat both carrion and actively pursued prey. Especially large prey is held in the turtle's beak and torn apart with its claws. Painted turtles do not chew food. Instead, they use their beaks to slice the food into pieces which they swallow whole.

Painted turtles are vulnerable to predation throughout their development and into adulthood. Many animals such as raccoons, several types of squirrels, chipmunk, woodchucks, skunk, badger, foxes, fish crows, garter snakes and humans will prey on turtle nests. Newly hatched turtles are eaten by rats, muskrat, mink, raccoons, snapping turtles, snakes, bullfrogs, large fish, herons, and water bugs. Adult turtles are preyed upon by alligators, raccoons, bald eagles, osprey, and red shouldered hawks. Humans pose many threats to painted turtles through habitat destruction, the use of pesticides, vehicles on roadways and the pet trade. When a painted turtle feels threatened, it may kick and scratch, bite and urinate. Painted turtles that have avoided predators and disease have been known to live longer than thirty years in the wild.